Kidney stone suction device

ABSTRACT

A method of using a suction device to remove an object from a subject&#39;s body includes extending a suction device into the body through a lumen of a medical device and expanding the suction head from a contracted configuration to an expanded configuration within the body. The suction head may be provided at a distal end of an elongate conduit. The method may also include applying suction to move the object into the expanded suction head, and removing the suction device with the object from the body.

CROSS-REFERENCE TO RELATED APPLICATIONS

The application claims the benefits of priority from U.S. ProvisionalApplication No. 62/037,456, filed on Aug. 14, 2014, which isincorporated by reference herein in its entirety.

TECHNICAL FIELD

Embodiments of the present disclosure relate generally to endoscopicsuction devices and methods of using the suction devices. In particular,embodiments of the present disclosure relate to suction devices andmethods for the extraction of stone fragments from the urinary tract ofa patient.

BACKGROUND

Open surgical intervention was once the standard treatment for theremoval of calculi or stones from the urinary tract of a patient. Butother less invasive techniques, such as ureteroscopy, have emerged assafe and effective alternatives to open surgery. During ureteroscopy,the doctor inserts an ureteroscope into the urinary tract through anatural opening in the body and positions the scope proximate the kidneystone. The stone may then be captured and removed from the body using asmall basket that extends into the urinary tract through theureteroscope. While smaller stones may be removed in one piece, largerstones may need to be broken up (or fragmented) before they can besuccessfully removed. Many techniques, such as lithotripsy, exist tobreak up stones within the body.

Lithotripsy devices direct energy (electrohydraulic, ultrasonic,electromechanical, laser, etc.) through a probe to fragment the stone.These devices may be introduced into the body through the working lumenof the ureteroscope, or may be introduced percutaneously. Inpercutaneous endoscopic techniques, a lithotripsy device may beintroduced into the body through a small puncture in the body. Thedevice may be positioned proximate the stone and focused shock waves (oranother energy) may be applied to the stone to break the stone intomultiple fragments. The fragments may then be allowed to pass naturallyout of the body or may be removed using a basket.

In some cases, it may be desirable to remove all the stone fragmentsfrom the body to prevent stone recurrence and stone migration. Largerstone fragments may be successfully removed using the basket. However,smaller fragments (typically less than 1 mm) may be difficult to removeusing the basket. In some cases, a suction tube of the lithotripsydevice may be used collect the smaller stone fragments. However, removalof stone fragments though the suction tube may result in clogging thatnecessitates repeated removal, cleaning and reinsertion of the tubeduring an operation. The methods and systems of the current disclosuremay rectify some of the deficiencies described above.

SUMMARY OF THE DISCLOSURE

Embodiments of the present disclosure include medical devices, such as asuction tool, that may be used to remove material such as kidney stonefrom a patient's body, and methods of use thereof.

In one example, an endoscopic suction device is disclosed. The suctiondevice may include an elongate conduit extending from a proximal end toa distal end along a longitudinal axis. The proximal end may beconfigured to be coupled to a vacuum source and the distal end may beconfigured to extend into a subject's body. The suction device may alsoinclude an expandable suction head at the distal end of the elongateconduit, the suction head may be configured to expand from a contractedconfiguration to an expanded configuration within the body.

Additionally or alternatively, the suction device may further includeone or more of the following features: the distal end of the elongateconduit may be sized to extend into the body through a lumen of amedical device and the suction head may be configured to transform froma contracted configuration within the lumen to an expanded configurationoutside the lumen; the lumen may be part of an ureteroscope; the suctionhead may be self-expandable; the suction head may include a shape-memoryalloy; the device may further include an activation device configured toapply energy to the suction head to transform the suction head from thecontracted configuration to the expanded configuration; suction headincludes a filter; in the expanded configuration, a cross-sectional areaof the suction head transverse to the longitudinal axis decreases from adistal-most end of the suction head to a proximal end of the suctionhead; a cross-sectional area of the suction head transverse to thelongitudinal axis is greater in the expanded configuration than in thecontracted configuration; the elongate conduit and the suction head maybe formed as a single part; the elongate conduit and the suction headmay be two parts attached together; the elongate conduit may include aflexible polymeric tube; the proximal end of the elongate conduit mayinclude a handle; the proximal end of the elongate conduit may include aluer fitting adapted to connect the elongate conduit to the vacuumsource; and in the expanded configuration, the suction head may have oneof a wine glass shape, a conical shape, or a cylindrical shape.

In an additional or alternative example, method of using a suctiondevice to remove an object from a subject's body is disclosed. Thesuction device may include an expandable suction head at a distal end ofan elongate conduit. The method may include extending the suction deviceinto the body through a lumen of a medical device and expanding thesuction head from a contracted configuration to an expandedconfiguration within the body. The method may also include applyingsuction to move the object into the expanded suction head, and removingthe suction device with the object from the body.

Additionally or alternatively, the method may include one or more of thefollowing features: expanding the suction head may include transformingthe suction head from a contracted configuration within the lumen to anexpanded configuration outside the lumen; removing the suction devicemay include removing the suction device through the lumen; removing thesuction device may include removing the lumen along with the suctiondevice from the body; the suction head may be self-expandable.

In an additional or alternative example, method of removing a kidneystone from a subject's urinary tract is disclosed. The method mayinclude inserting a medical device with a lumen into the urinary tractand extending a suction device into the urinary tract through the lumen.The suction device may include a self-expandable suction head at adistal end of an elongate conduit. The method may also include expandingthe suction head from a contracted configuration within the lumen to anexpanded configuration outside the lumen. The method may further includeapplying suction to move the stone into the expanded suction head, andremoving the suction device with the stone from the urinary tract.

Alternatively or additionally, the method may further include one ormore of the following features: inserting a medical device may includeinserting a ureteroscope into the urinary tract; in the expandedconfiguration, a cross-sectional area of the suction head transverse toa longitudinal axis of the suction head may decrease from thedistal-most end of the suction head to a proximal end of the suctionhead; removing the suction device may include removing the medicaldevice along with the suction device from the urinary tract; across-sectional area of the suction head transverse to a longitudinalaxis of the suction head may be greater in the expanded configurationthan in the contracted configuration.

Additional objects and advantages of the present disclosure will be setforth in part in the description which follows, and in part will beunderstood from the description, or may be learned by practice of theclaimed disclosure. The objects and advantages of the claimed disclosurewill be realized and attained by means of the elements and combinationsparticularly pointed out in the appended claims.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the disclosure, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate exemplary embodiments of thepresent disclosure and together with the description, serve to explainthe principles of the disclosure.

FIG. 1 illustrates the urinary tract of a female patient;

FIG. 2 illustrates an exemplary suction tool of the current disclosure;

FIG. 3A illustrates an the suction head of FIG. 2 in an exemplarycontracted configuration;

FIG. 3B illustrates an the suction head of FIG. 2 in an exemplaryexpanded configuration;

FIGS. 4A-4C illustrate exemplary embodiments of the suction head of thesuction tool of FIG. 2;

FIGS. 5A-5D illustrate some exemplary shapes of the suction head of thesuction tool of FIG. 2;

FIG. 6 is a flow chart that illustrates an exemplary method of using thesuction tool of FIG. 2.

DESCRIPTION OF THE EMBODIMENTS Overview

The present disclosure is drawn to suction devices and related systemsand methods. Specifically, the present disclosure is drawn to suctiondevice for removing material from a body and methods of using thesuction device in a medical procedure. The suction device may include anelongate conduit with an expandable head at its distal end. Referencewill now be made in detail to aspects of the present disclosure,examples of which are illustrated in the accompanying drawings. Whereverpossible, the same reference numbers will be used throughout thedrawings to refer to the same or like parts. The term “distal” refers toa portion farthest away from a user when introducing a device into apatient. By contrast, the term “proximal” refers to a portion closest tothe user when placing the device into the patient.

Exemplary Aspects

FIG. 1 illustrates the pelvic region of a female patient with a kidneystone 20 (“stone”) embedded in a ureter 16 of the urinary tract 100. Asknown in the art, the urinary tract 100 includes a pair of kidneys 8, apair of ureters 16, a bladder 14, and a urethra 12. Stones in the ureter16 can cause extreme pain as the body attempts to push them through theureter 16 into the bladder 14. In some cases, a doctor (typically aurologist) performs a procedure known as ureteroscopy to remove thesestones 20 from the body. In this procedure, the doctor inserts aureteroscope 10 (a thin flexible viewing instrument) into the bodythrough the vagina, and pushes the ureteroscope 10 into the ureter 16,to position its distal end 22 proximate the stone 20. After theureteroscope 10 is suitably positioned, a small basket 18 may beintroduced into the ureter 16 through a lumen of the ureteroscope 10,and maneuvered to capture the stone 20 therein. The basket 18 along withthe captured stone may then be removed from the body through theureteroscope 10. Although FIG. 1 illustrates the stone 20 as beingembedded in a ureter 16 (a medical condition referred to asureterolithiasis), it should be noted the stone 20 may be locatedanywhere in the urinary tract 100.

If the stone 20 is too large to be removed as one piece using the basket18, a known procedure (for example, lithotripsy, percutaneousnephrolithotomy (PCNL), etc.) may be used to break a large stone 20 intosmaller fragments. Since procedures used to break stones into smallerfragments are known in the art, these techniques are not discussedherein. In some of these procedures, focused energy (ultrasonic energy,laser energy, etc.) may be used to break the stone 20 into smallerfragments. The larger of these fragments may be removed using basket 18.The smaller fragments, which may be too small to be removed using thebasket 18, may be collected and removed from the body using a suctiontool introduced into the ureter 16 through a lumen of the ureteroscope10.

FIG. 2 illustrates an exemplary suction tool 30. Suction tool 30 mayinclude an elongate conduit 32 that extends from a proximal end 34 to adistal end 36 along a longitudinal axis 40. The distal end 36 of theconduit 34 may include an expandable suction head 38 and the proximalend 34 may include a handle 42. Conduit 32 may also include a port 44that is adapted to be coupled to a vacuum source (house vacuum, vacuumpump, etc.) to provide suction at the distal end 36 of the conduit 32.Although not illustrated, port 44 may include a luer fitting to make aleak-free connection to the vacuum source. Conduit 32 may be made of aflexible material (for example, a polymeric tube), a rigid material, ora combination of both flexible and rigid materials. In some embodiments,conduit 32 may be braided or wound with plastic or metal fibers toimprove conduit's resistance against kink-formation or against collapseunder vacuum pressure. In some embodiments, conduit 32 may includecoatings on its inside or outside surface for various purposes, forexample, for protection against corrosion and/or by body fluids. Ingeneral, conduit 32 may have any dimension suitable for its intendeduse. In some embodiments, an elongated polymeric or polypropylene tubemay serve as conduit 32.

In some embodiments, as illustrated in FIG. 2, suction head 38 andconduit 32 may be formed as a single part (that is, integrally formed).In other embodiments, a separate (or discrete) suction head 38 may beattached to the distal end 36 of the conduit 32. The suction head 38 maybe attached to the conduit 32 by any known method (interference fit,adhesives, etc.). Suction head 38 may be configured to transform from acontracted configuration to an expanded configuration. In the expandedconfiguration, the suction head 38 may have a larger diameter and/orcross-sectional area (in a plane normal to the longitudinal axis 40)compared to its diameter and/or cross-sectional area in the contractedconfiguration. The suction head 38 may extend through the lumen of theureteroscope 10 (or another lumen) in a contracted configuration, andtransform to its expanded configuration when it extends out of thelumen. In some embodiments, the suction head 38 may be activated to itsexpanded configuration after the suction head 38 exits the lumen.

FIGS. 3A and 3B illustrate exemplary contracted and expandedconfigurations of the suction head 38. FIG. 3A illustrates the suctionhead 38 in its contracted configuration within a lumen 50 ofureteroscope 10, and FIG. 3B illustrates the suction head 38 in itsexpanded configuration outside the lumen 50. Although lumen 50 isdescribed as a lumen of ureteroscope 10, it should be noted that, ingeneral, lumen 50 may be a lumen of any device (catheter, sleeve, etc.).In some embodiments, the suction head 38 may be a self-expandingstructure (or may include a self-expanding structure) configured toautomatically transform from the contracted configuration to theexpanded configuration when the suction head 38 extends from the lumen50. In some embodiments, the suction head 38 may transform from itscontracted to its expanded configuration when it is activated. Thesuction head 38 may be activated in any manner. In some embodiments, anactivation mechanism may be provided in the handle 42 of the suctiontool 30 to activate the suction head 38. The activation mechanism mayinclude a knob 46 that may be controlled to activate the suction head38. In some embodiments, translation or rotation of the knob 46 mayprovide the energy (heat, current, etc.) required to activate thesuction head 38. In some embodiments, mechanical connections (wires,links, etc.) between the knob 46 and the suction head 38 may transformthe suction head 38 between the contracted and expanded configurations.

In some embodiments, suction head 38 may include a shape-memorymaterial. Any known shape-memory material (nickel titanium alloys(Nitinol), copper-aluminum-nickel alloys, shape-memory polymers, etc.)may be used to form suction head 38. As is known in the art,shape-memory materials may have a shape-memory effect and apseudo-elastic effect. Because of the shape-memory effect, ashape-memory material may undergo deformation and remain in its deformedstate until heat (or some other form of energy) is applied to it. Whenheat is applied, the shape-memory material may recover its originalundeformed shape. Because of the pseudo-elastic effect, the shape-memorymaterial may undergo large deformations upon the application of forceand recover its original shape when the force is removed.

In some embodiments, as illustrated in FIG. 4A, the suction head 38 maybe formed of a shape-memory material. For example, in some embodiments,the walls of the suction head 38 may be formed of a wire mesh (or aweave) of a shape-memory material. In some embodiments, the mesh may becoated with another material (for example, a polymeric material) toclose the gaps between the wires. In some embodiments, as illustrated inFIGS. 4B and 4C, the suction head 38 may include material segments 52positioned in a matrix material 54. The matrix material 54 may be thesame material as the conduit 32 or a different material. The materialsegments 52 may include components (wires, strands, mesh, etc.) of anyshape and size. In some embodiments, material segments 52 may be made ofa shape-memory material. The material segments 52 may be configured totransform the suction head 38 to its expanded configuration when theseelements 52 return to their undeformed configuration. In someembodiments, as illustrated in FIG. 4B, these material segments 52 maybe embedded in the matrix material 54. In other embodiments, asillustrated in FIG. 4C, the material segments 52 may form a scaffoldinginside or outside the matrix material 54. In some embodiments, some orall of the materials of suction head may be transparent or translucentfor better visualization. In some embodiments, these materials may besoft and compliant to not cause trauma to the treated area.

When the suction head 38 is positioned in the lumen 50, the materialsegments 52 may be in their deformed state, and the suction head 38 maybe in its contracted configuration. Extending the suction head 38 out ofthe lumen 50 may allow the material segments 52 to return to theirundeformed shape and transform the suction head 38 to its expandedconfiguration. In such embodiments, the walls of the lumen may apply aninward constraining force to retain the suction head 38 in itscontracted configuration within the lumen. Extending the suction head 38out of the lumen may release the constraining force and transform thesuction head 38 to its expanded configuration. In some embodiments, thematerial segments 52 may return to their undeformed state, and transformthe suction head 38 to its expanded configuration, upon the applicationof heat. In some embodiments, activation (rotating, translating, etc.)of knob 46 on the handle 42 may provide the direct to the suction head38 to transform the suction head from its contracted to its expandedconfiguration. For example, in some embodiments, knob 46 may activate aheater that heats material segments 52 of a suction head 38. In someembodiments, an air or a saline bladder may be operatively coupled withthe suction head 38. This bladder may expand the suction head 38 whenfilled with air or saline.

In some embodiments, the suction tool 30 may include a sleeve. In suchembodiments, the suction tool 30 may be inserted into the sleeve and thesleeve may be introduced to the ureter 16 through the lumen 50. Thesuction head 38 may be in its contracted configuration within thesleeve. Retracting the sleeve (that is moving the sleeve in the proximaldirection with respect to the suction tool 30) may remove theconstraining force of the sleeve from the suction head 38 and transformthe suction head 38 to its expanded configuration.

The suction head 38 may have any size and shape. In general, the suctionhead 38 may have an enlarged shape. In some embodiments, thecross-sectional shape (in a plane perpendicular to the longitudinal axis40) of the suction head 38 may be circular. However, this is not arequirement. It is contemplated that in some embodiments, thecross-section shape may be square, rectangular, elliptical, orpolygonal. As illustrated in FIGS. 4A-4C, in some embodiments, thesuction head 38 may have a wine glass shape (in the plane of the paper).In such embodiments, the cross-sectional area (in a plane perpendicularto the longitudinal axis 40) of the suction head 38 may decrease fromits distal-most end towards the proximal direction. FIGS. 5A-5Dillustrate some other exemplary shapes of suction heads 138-438. In someembodiments, as illustrated in FIG. 5A, the suction head 138 may have asubstantially tubular (or cylindrical) shape. In some embodiments, afilter 60 may be provided in the suction head 138. The filter 60 mayprevent (or reduce) stone fragments 70 from entering the conduit 32 andthereby prevent (or reduce) clogging of the suction tool 30. Smallerstone fragments that enter the conduit 32 through the filter 60 may becollected at the proximal end. In some embodiments, as illustrated inFIG. 5B, suction head 238 may have a substantially conical shape. Insome embodiments, as illustrated in FIG. 5C, suction head 338 may have asubstantially hemispherical shape. In some embodiments, as illustratedin FIG. 5D, suction head 438 may have an offset shape that is configuredto prevent blocking a camera 58 or a light source at the distal end ofthe ureteroscope 10.

FIG. 6 is a flow chart that illustrates an exemplary method of usingsuction tool 30 to remove a kidney stone 20 from the urinary tract 100of a patient. In the discussion below, reference will be made to FIGS.1, 3A, and 3B in addition to FIG. 6. If the stone 20 is too large to beremoved as one piece, the stone 20 may be fragmented or broken tosmaller pieces using any known technique (step 210). The suction tool 30may be introduced into the urinary tract 100 and positioned proximatethe location of the stone fragments 70 (step 220). The suction tool 30may be directed into the urinary tract 100 through a lumen 50 ofureteroscope 10 or through a lumen of another device. The suction head38 of the suction tool 30 may be in its contracted configuration withinlumen 50. Outside the lumen, the suction head 38 may transform to itsextended configuration (step 230). In embodiments of suction tool 30with a self-expanding suction head 38, the suction head 38 may transformto its expanded configuration automatically when it exits from the lumen50. In some embodiments, some form of energy (heat, current, etc.) maybe directed to the suction head 38 to transform the suction head 38 fromthe contracted to the expanded configuration. The stone fragments 70 maybe collected in the suction head 38 using suction (step 240). In someembodiments, the ureteroscope 10 or the suction tool 30 may bemaneuvered to move the suction head 38 in the urinary tract 100 andcollect stone fragments that have shifted.

After the stone fragments 70 are collected in the suction head 38, thesuction head 38 may be closed to prevent (or minimize) the escape ofthese stone fragments back into the urinary tract 100 (step 250). Insome embodiments, the suction head 38 may be closed by pulling thesuction tool 30 in a proximal direction. When the suction tool 30 ispulled in the proximal direction, the suction head 38 at least partiallyretracts into the lumen 50 and the suction head 38 moves towards itscontracted configuration. In some embodiments, the closed configurationof a suction head 38 is the same as its contracted configuration.However, it should be noted that based on the volume and size of thestone fragments 70 in the suction head 38, in some embodiments, theclosed configuration of the suction head 30 may not be the same as itscontracted configuration. In such cases, when pulled in the proximaldirection, the suction head 38 may not retract completely into the lumen50. Instead, a portion of the suction head 38 may remain outside thelumen 50 with the walls of the suction head 38 forced towards thelongitudinal axis 40 by the inner walls of the lumen 50. In general, theclosed configuration of a suction head 38 may be a configuration that isbetween its contracted and expanded configurations. In the closedconfiguration, the stone fragments 70 may be tightly held between thewalls of the suction head 38 or may be enclosed by the walls.

The suction tool 30 with the stone fragments may then be withdrawn fromthe urinary tract 100 (step 260). In some embodiments, the suction tool30 may be withdrawn from the urinary tract 100 through the lumen 50 ofthe ureteroscope 10. In some embodiments, the suction tool 30 along withthe ureteroscope 10 may be withdrawn from the urinary tract 100together. It should be noted that the method of FIG. 6 is only exemplaryand that many variations can be made to the illustrated method. Forinstance, in some embodiments, the fragmenting step (step 210) may beeliminated and the suction tool 30 may be used to remove an unfragmentedstone from the body.

Using the exemplary devices and methods described herein, a medicalprofessional may readily and accurately remove kidney stones from apatient's body. It is understood, however, that while embodiments of thepresent disclosure have been described with reference to removing kidneystones from the urinary tract, the teachings of the present disclosuremay be used to remove material from any lumen of the body. Further, thedevices herein may be single-use which can be discarded after one use ormay be used again after sterilization.

Other embodiments of the present disclosure will be apparent to thoseskilled in the art after consideration of the specification and practiceof the embodiments disclosed herein. It is intended that thespecification and examples be considered as exemplary only, with a truescope and spirit of the disclosure being indicated by the followingclaims.

1-20. (canceled)
 21. A method of using a suction device to remove anobject from a subject's body, the suction device including an expandablesuction head at a distal end of a conduit, comprising: extending thesuction device into the body through a lumen of a medical device;expanding the suction head from a contracted configuration to anexpanded configuration within the body; applying suction to move theobject into the expanded suction head; preventing the object from movingproximally beyond the expanded suction head; and removing the suctiondevice with the object from the body.
 22. The method of claim 21,wherein expanding the suction head includes transforming the suctionhead from a contracted configuration within the lumen to an expandedconfiguration outside the lumen.
 23. The method of claim 22, whereinexpanding the suction head from a contracted configuration to anexpanded configuration includes applying heat or current to the suctionhead.
 24. The method of claim 23, further including contracting thesuction head from the expanded configuration to a closed configurationby removing the applied heat or current.
 25. The method of claim 21,wherein removing the suction device includes removing the suction devicethrough the lumen of the medical device.
 26. The method of claim 21,wherein removing the suction device includes removing the medical devicealong with the suction device from the body.
 27. The method of claim 21,wherein the suction head is self-expandable.
 28. The method of claim 21,wherein preventing the object from moving proximally beyond the expandedsuction head includes a filter positioned at a junction between aproximal end of the suction head and the distal end of the conduit. 29.A method of removing a kidney stone from a subject's urinary tract,comprising: inserting a medical device with a lumen into the urinarytract; extending a suction device into the urinary tract through thelumen, the suction device including an expandable suction head at adistal end of a conduit; expanding the suction head from a contractedconfiguration within the lumen to an expanded configuration outside thelumen; applying suction to move the stone into the expanded suctionhead; and removing the suction device with the stone from the urinarytract.
 30. The method of claim 29, wherein inserting a medical deviceincludes inserting a ureteroscope into the urinary tract.
 31. The methodof claim 29, wherein, in the expanded configuration, a cross-sectionalarea of the suction head transverse to a longitudinal axis of thesuction head decreases from the distal-most end of the suction head to aproximal end of the suction head.
 32. The method of claim 29, whereinremoving the suction device includes removing the medical device alongwith the suction device from the urinary tract.
 33. The method of claim29, wherein a cross-sectional area of the suction head transverse to alongitudinal axis of the suction head is greater in the expandedconfiguration than in the contracted configuration.
 34. The method ofclaim 29, further including preventing the object from moving proximallybeyond the expanded suction head.
 35. The method of claim 29, whereinexpanding the suction head from a contracted configuration within thelumen to an expanded configuration outside the lumen includes applyingheat or current.
 36. The method of claim 35, further includingcontracting the suction head from the expanded configuration to a closedconfiguration by removing the applied heat or current.
 37. An endoscopicsuction device, comprising: a conduit extending from a proximal end to adistal end along a longitudinal axis, the proximal end configured to becoupled to a vacuum source and the distal end configured to extend intoa subject's body; an expandable suction head at the distal end of theconduit, the expandable suction head being configured to expand from acontracted configuration to an expanded configuration within the body inresponse to the application of heat or current, and a filter positionedtransverse to the longitudinal axis, wherein the filter spans across-sectional area of the endoscopic suction device to preventmaterial from entering the conduit.
 38. The device of claim 37, whereina cross-sectional area of the expandable suction head transverse to alongitudinal axis of the suction head is greater in the expandedconfiguration than in the contracted configuration.
 39. The device ofclaim 37, wherein the expandable suction head is configured to contractfrom the expanded configuration to the contracted configuration inresponse to the removal of the applied heat or current.
 40. The deviceof claim 39, wherein the expandable suction head is configured to atleast partially surround material prevented by the filter from enteringthe conduit.